1. Field of the Invention
This invention relates an ampoule sealing apparatus, particularly an apparatus for evacuating air from ampoules containing samples of proteins or peptides and then sealing the ampoules.
In the pharmaceutical and biotechnology industries, there often arises the need to analyze the amino acid composition of various proteins and peptides. This amino acid analysis is typically a multi-step procedure, the end result of which is the analytical determination of the concentration and the amino acid composition of the protein (or peptide) sample. The first step in this analytical process involves the hydrolysis of the protein (or peptide) to its constituent amino acids by use of a concentrated acid for effecting the hydrolysis. The hydrolyzing acid is removed and then the sample is reconstituted in a suitable buffer for analysis by an appropriate liquid chromatographic system in which the amino acids are separated and quantified.
The complete hydrolysis of the protein (or peptide) to free amino acids is accomplished by heating the sample at about 110.degree. C., for a suitable period of time, for example, from 8 to 24 hours, in the presence of the concentrated hydrolyzing acid. Oxygen must be removed from the sample, prior to heating it in order to prevent the oxidative decomposition of various amino acids, especially methionine and tryptophan. Typically, the sample is dissolved in about 1 milliliter of the concentrated acid and then is placed in a commercially available ampoule suitable for flame sealing. A high vacuum is applied to the ampoule and the ampoule is vigorously shaken in order to aid in the degassing of the sample. The ampoule is then placed in a high temperature flame where the vacuum serves to collapse the molten glass and provide the seal. These operations are typically performed manually and often result in the operator burning his fingers during the sealing of the ampoules and they cause the formation, on the ampoule, of a thin-walled portion which is much more subject to breakage than the other, normal thickness portions thereof. Also, the ampoule sealing conditions are not strictly reproducible so that the results are not as precise as is desired.
2. Description of the Prior Art
U.S. Pat. No. 1,864,023 to Ledig discloses a machine for sealing hollow glass blanks for ampoules in which a vacuum is applied to an ampoule after the ampoule has been filled with the required quantity of contents. The ampoule is then sealed by the use of burners which revolve around the neck of the ampoule. U.S. Pat. No. 3,188,778 to Winer et al discloses an apparatus for dosing the arc tubes of high pressure mercury discharge lamps. The arc tubes are evacuated and filled with an ionizable starting gas by an automatic exhaust machine, mercury is inserted into the arc tube, a striker arm taps the tubulation part of the arc tube in order to ensure that all of the mercury has fallen into the tube and an annular burner seals off the arc tube. U.S. Pat. No. 2,896,381 to Lange discloses the use of an inert decontaminated gas to flush an ampoule and a sealing flame to close the neck of the ampoule. U.S. Pat. No. 4,596,109 to Miller discloses the deposition of an antibody or an antigen-coated ball in a tube and applying a vacuum on the tube by a vacuum hose while applying heat to the top of the tube by a pair of soldering irons in order to seal the tube. U.S. Pat. Nos. 2,198,752 and 2,353,985 to Barr disclose apparatuses for preserving biologically active substances in which the substance is sealed in a vial by pulling a vacuum on the vial, inserting a rubber stopper into the neck of the vial and using a flame to seal the neck of the vial above the stopper. However, none of the prior art references teach or suggest the apparatus of the present invention.